The integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs, where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs.
Many of the technological advances in semiconductors have occurred in the field of memory devices, and some of these involve capacitive structures. Capacitive structures are components for many data manipulation and data storage applications. Such capacitive structures include two conductive electrodes on opposing sides of a dielectric or other insulating layer, and they may be categorized based on the materials employed to form the electrodes. For example, in metal-insulator-metal (MIM) capacitors, the electrodes are substantially metal. MIM capacitors offer the advantage of a relatively constant value of capacitance over a relatively wide range of voltages applied thereto. MIM capacitors also exhibit a relatively small parasitic resistance. MIM capacitors are compatible with CMOS fabrication processes. Current fabrication methods and structures, while suitable in many respects, can struggle to meet the desired performance and reliability criteria, such as frequency response and breakdown voltage tailing. Therefore, further improvements in this area are needed.